Yb/Sr optical clock comparison at 2.2E-18 uncertainty over a 1350-km fiber link
Auteurs : Lei Hou, Xiang-Pei Liu, Zhuan-Xian Xiong, Fa-Xi Chen, Wen-Xuan Song, Jian-Yu Guan, Qiang Zhu, Yu-Chen Zhang, Xiang Zhang, Bing Wang, De-Zhi Xiong, De-Quan Kong, Jia-Hao Zhang, Long-Fei Liao, Shao-Mao Wang, Xing-Yang Cui, Ping Xu, Peng Liu, Jie Li, Xiao Jiang, Ling-Xiang He, Li-Bo Li, Qi Shen, Youchao Xie, Lei Wang, Sheng-Kai Liao, Juan Yin, Cheng-Zhi Peng, Wen-Bin Shen, Bao-Long Lu, Han-Ning Dai, Yu-Ao Chen, Qiang Zhang, Hai-Feng Jiang, Jian-Wei Pan
Résumé scientifique
Redefining the International system of Units (SI) second requires independent frequency-ratio measurements between clocks based on different laboratories, with an overall uncertainty below 5E-18, to validate individual clock evaluations through consistency checks. Reaching this uncertainty over long distances has remained challenging. So far, comparisons at this level have been achieved only a few times, between co-located clocks, and their results disagree markedly. Previous high-precision comparisons have therefore been limited to local or kilometre-scale links. Here we compare a ytterbium optical lattice clock in Wuhan with a strontium optical lattice clock in Shanghai over a phase-stabilized fiber link spanning 1350 km, and determine the Yb/Sr frequency ratio to be 1.207 507 039 343 337 716 0(26), with a Bayesian statistical uncertainty of 1.14E-18 and a total uncertainty of 2.18E-18. To our knowledge, this is the first intercity long distance frequency-ratio measurement, whose total uncertainty reaches the level required by the redefinition roadmap. The measured ratio exhibits a significant correlation with Earth tides and its response agree with the model within the statistical uncertainty. At intercity scale, this comparison demonstrates the capability of an optical-clock network for frequency comparison and Earths gravitational-potential sensing, a key step toward a wide-area optical-clock network.
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En bref
Deux horloges optiques au Royaume-Uni et en Allemagne concordent avec une incertitude relative de 4,8 × 10⁻¹⁸, et leur comparaison renforce les contraintes sur certaines violations de l’invariance de Lorentz.
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Résumé scientifique
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Résumé scientifique
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Résumé scientifique
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Résumé scientifique
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Résumé scientifique
We report a systematic uncertainty of 9.2×10−19 for the Sr1 optical lattice clock at the University of Science and Technology of China (USTC), achieving accuracy at the level required for the roadmap of the redefinition of the SI second. A finite-element model with in situ-validated, spatially-resolved chamber emissivity reduced blackbody radiation (BBR) shift uncertainty to 6.3×10−19. Concurrently, the externally mounted lattice cavity, by providing a larger beam waist, reduced the atomic density and thereby suppressed the density shift. Enhanced lattice depth modulation consolidated lattice light shift uncertainty to 6.3×10−19 by enabling simultaneous determination of key polarizabilities …
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Résumé scientifique
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Résumé scientifique
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Les travaux antérieurs sur lesquels il s’appuie
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Résumé scientifique
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Résumé scientifique
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Résumé scientifique
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